OVERALL: I love this product! I got a red dot that can hold the recoil of a 12GA 2.75" slug. PERFECT! I've also used it on my Glock 17 (with a mount) and it works great!
BEST FEATURES: The dot is perfectly round and there is no blur around it. The brightness setting is GOLD. 12 ON settings and OFF allow you to set this red dot to the exact brightness you desire. Setting it too bright will make it appear larger which can be great for close-quarter-combat (CQC). I've left this thing on over night many times and have left it on for hours and hours at the shooting range. The battery only recently began failling at extremely low brightness settings. But that's because I made the mistake of storing it in a box without taking the battery out.
HOLDS ZERO: HELL YES! I've tried it on a Mossberg 500A (20" barrel) and I only shoot full-power slugs with it. But not the scope rings... read below.
PROBLEM1: Well the screws and allen wrenches that come with it are soft metals and round off way too easily. You CANNOT tighten them enough to get a tight grip on the scope. So after 10 12GA slugs, the sight physically slides forward in the scope rings. Sad. I tried tightening it more and damaged the screws/tool. Well the tool was not a problem... I have better ones plus I just cut the one they gave me with a dremel. But the screws were damaged beyond repair and would continue to slip. My solution: I held the screw tightly with plyers. I started up my Dremel (well it's an AllState but w/e) with a cut-off wheel. I put it on high speed and brought it down straight on the center of the allen screw and cut out a nice thin groove in the center so that I could drive it with a flathead screwdriver. I found a screw driver that was the perfect size (or I could have cut one to fit)... it was big enough to hold the allen screw but not too big to fit in the holes in the scope rings. I was able to tighten it enough to fix the problem.
PROBLEM2: When I re-installed it I had repositioned it on my picatinny rail and for some reason I couldn't QUITE get the sight zeroed. I kept adjusting the screw but it was at the end of it's range and was not moving the dot any further. I repositioned the sight yet again and the problem was solved.
PRICE: I bought a BSA red dot for a discounted $35 (unused) and it couldn't hold zero on a glock (mounted to the frame not the slide). I discovered that it was a clone of all the other red dots like it and they all have the same problem. I spoke with some people and they all said anything under $200-$300 is going to be for air-soft and fail to hold zero on a real gun. Over the years I've used this optic a lot on the batteries that came with it. I LOVE IT! I also love the 2" groups I can easily shoot with my Glock.
Pros: HOLDS ZERO ON PRETTY MUCH ANYTHING LEGAL IN CALIFORNIA!
Cons: Screws/Wrench that come with the scope rings are TERRIBLE.
This review was written in the old system and had content requirements that are different than reviews written today.